Modern server applications, such as data centers and server rack environments, typically use multiple server nodes that cooperate together to provide services to clients. Conventional server motherboards are typically used in such server nodes. A server motherboard includes at least a circuit board having a number of sockets configured to fit various components, one or more processors (e.g. CPUs), and an interface for performing external communication. Other components may also be used. Some of these may be incorporated into the circuit board or may fit dedicated socket(s) on the circuit board. The CPUs include connectors having a form factor that mates with CPU sockets on the circuit board. Stated differently, the CPU sockets on the circuit board have the same form factor as the connectors (or pins) for the CPU. With latest server architecture, the CPU sockets on the circuit board are coupled to dedicated memory, such as DIMM, for each CPU. This dedicated memory is accessible through the CPU. The interface for performing external node-to-node communication is generally an Ethernet interface. Such an input/output interface typically includes Ethernet controller coupled to a port. The port is typically a PCIE port from southbridge which is interconnected to the first of the two CPUs.
In operation, each server board performs calculations using at least its internal CPUs. Dedicated memory for each CPU may provide faster access to items in the dedicated memory. For external communication data are routed to/from their locations in memory from/to the Ethernet interface. Similarly, CPU commands, requests, and other information are routed from/to the CPU to/from the Ethernet interface. Thus, server boards may operate individually or together to provide the desired operations.
In server applications, low latency and fast communication between server nodes is desirable. The server boards in such an environment exchange data and perform communication with CPUs on other server boards through the Ethernet I/O interface. Because of the location of the Ethernet controller and port, there may be a long path between the Ethernet interface and some data on the server board. Further, the port is generally universal to all the data through the Ethernet interface. Thus, there may be a relatively large overhead and long latency for memory data exchanges. This is undesirable.
Many server boards include first and second CPUs residing in first and second CPU sockets on the circuit board. However, some server applications may not need two CPUs in the server board. If a single CPU is adequate for the computational needs, the second socket in the circuit board may be left empty. Use of a single CPU in the server board may reduce the power consumption, which is generally desirable. There is also a cost savings due to the omission of the second CPU. However, as discussed above, each CPU socket and thus each CPU typically has dedicated memory. Leaving one of the CPU sockets empty may preclude access to the dedicated memory for that CPU socket. Thus, the reduction in power and cost achieved by omitting a CPU may be offset by limitations in the memory for the server board for many applications which require large memories but are not calculation intensive.
Accordingly, a server board having improved functionality is desired.